<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    #app {
      width: 320px;
      height: 320px;
      background-image: linear-gradient(to right, transparent 90%, #ccc 0),
        linear-gradient(to bottom, transparent 90%, #ccc 0);
      background-size: 8px 8px;
    }
  </style>
</head>
<body>
  <div id="app"></div>
</body>
</html>